Effects of a Theory-Based Education Program to Prevent ... - MDPI

Article

Effects of a Theory-Based Education Program to Prevent Overweightness in Primary School Children Paul L. Kocken 1,2, *, Anne-Marie Scholten 1,3 , Ellen Westhoff 1,4 , Brenda P. H. De Kok 1 , Elisabeth M. Taal 1 and R. Alexandra Goldbohm 5 Received: 2 November 2015; Accepted: 14 December 2015; Published: 4 January 2016 1

2 3 4 5

*

Netherlands organization for applied scientific research (TNO), Division of Child Health, P.O. Box 3005, 2301 DA Leiden, The Netherlands; [email protected] (A.-M.S.); [email protected] (E.W.); [email protected] (B.P.H.D.K.); [email protected] (E.M.T.) Leiden University Medical Center (LUMC), Department of Public Health and Primary Care, P.O. Box 9600, 2300 RC Leiden, The Netherlands The Hague University of Applied Sciences, Nutrition and Dietetics, P.O. Box 13336, 2501 EH The Hague, The Netherlands Radboud Institute for Health Sciences, Radboud university medical center, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands Netherlands organization for applied scientific research (TNO), Division of Life Style, P.O. Box 3005, 2301 DA Leiden, The Netherlands; [email protected] Correspondence: [email protected]; Tel.: +31-88-866-6218

Abstract: The effectiveness of the “Extra Fit!” (EF!) education program in promoting healthy diet and physical activity to prevent and reduce overweightness among primary school children aged 9 to 11 was evaluated. A randomized controlled design was carried out in 45 primary schools (n = 1112) in the Netherlands, 23 intervention and 22 control schools. The intervention schools received the education program for two successive school years in grades (U.S. system) 4, 5, and 6 (mean 7.6 h during 16 weeks per school per year). The control schools followed their usual curriculum. No positive effects of EF! were found with regard to behavior and anthropometric measures when follow-up measurements were compared to the baseline. However, from baseline to follow-up after one and two school years, the intervention group improved their knowledge score significantly compared to the control group. Moreover, an effect was observed for mean time spent inactively that increased more in the control group than in the intervention group. In conclusion, limited intervention effects were found for the intervention on knowledge and inactivity. To improve the effectiveness of education programs, we advise focusing on parental involvement, attractive lessons to enlarge the acceptability of the program, and multi-component environmental strategies. Keywords: overweight; primary school children; education program; RCT; nutrition; physical activity; behavioral determinants

1. Introduction Overweightness and obesity have become a worldwide problem [1]. Evidence from the literature shows that it is important to learn and establish healthy habits during the pre-adolescent period to prevent excessive weight gain [2–4]. Therefore, primary schools are a setting for the prevention of overweightness in children. Many reviews have summarized the effectiveness of interventions to prevent overweightness in children on anthropometric measurements, behavior (food consumption, physical activity or inactivity), or behavioral determinants. The effects of such intervention studies on anthropometric measures were often absent or produced inconclusive evidence [2,5]. However, a meta-analysis

Nutrients 2016, 8, 12; doi:10.3390/nu8010012

www.mdpi.com/journal/nutrients

Nutrients 2016, 8, 12

2 of 17

by Sobol-Goldberg et al. [6] concluded that more recent studies showed convincing evidence that school-based programs are at least mildly effective in reducing BMI, possibly because these programs tend to be longer, more comprehensive and included parental involvement. Behaviors most often linked to overweightness are low fruit and vegetable consumption, skipping breakfast, high fat and energy content and low fiber content of the diet and high soft drink consumption [7–9]. Many school-based interventions are aimed at improving fruit and vegetable consumption and small beneficial effects of such programs were reported [2]. In recent trials, Fairclough et al. [10] and Kipping et al. [11] did not find an increase in fruit and vegetable consumption, but Nyberg et al. [12] found a significantly higher vegetable intake in the intervention group. Effects on physical activity turned out to be small [10], absent [11] or only present in subgroups [12]. A systematic review by Dobbins et al. [13] concluded that school-based physical activity interventions led to an improvement in the proportion of children who engaged in moderate to vigorous physical activity during school hours. Interventions aimed at reducing sedentary behavior (e.g., television viewing, playing games) seem to be relatively efficient both as single-component intervention and in combination with other behaviors [14]. A meta–analysis by van Grieken et al. [15] showed that single and multiple health behavior interventions significantly decreased sedentary behavior and BMI. In general, although some studies reported promising effects, findings remain mixed [16] and there is doubt if beneficial results could be sustained or if they were biased by self-report. Effective interventions to prevent overweightness in primary school children have to address multiple behaviors, including nutrition, exercise and inactivity [2,7]. Moreover, to be effective, it is advised to have a theory-based foundation and address related psychosocial determinants of behavior such as attitudes, social norms and perceived behavioral control from the Theory of Planned Behavior (TPB) [7,17,18]. The study presented in this article is an evaluation of the intervention named “Extra Fit!” (EF!). The intervention combined elements of existing interventions aiming at the promotion of healthy nutrition and physical activity and the reduction of sedentary behavior and was thoroughly grounded in behavior change theory. The evaluation study used one-day food records with recall interviews and accelerometer instruments additional to self-report measurements in a two-year timeframe. The aim of EF! was to improve dietary habits, physical activity and inactivity behavior in order to prevent overweightness. The following research questions were addressed: What are the effects of the school-based program on dietary intake, physical activity and inactivity, BMI (prevalence of overweightness/obesity), and waist and hip circumference of primary school children? What are the effects of the program on related behavioral determinants: knowledge, attitude, perceived social norm, perceived behavioral control, and intention? 2. Experimental Section 2.1. Intervention The general target of EF! was to prevent or reduce overweightness in primary school children. The Intervention Mapping (IM) procedure was used to give the program a theory base and to specify performance and change objectives aimed at the children’s dietary intake, physical activity and inactivity [19]. The methods and strategies of the classroom and physical education activities of the EF! program were based on these performance and change objectives, the TPB determinants, materials of existing Dutch school-based interventions such as “Taste Lessons” [20] that had been proven partially effective, and the framework of the effective US intervention programs “Planet Health” and “Eat Well and Keep Moving” [21,22]. The carefully developed theoretical basis and the integral approach of the dietary, physical activity and inactivity behaviors was new compared to interventions that existed at the start of EF!. EF! was developed by three Dutch national health promotion organizations, i.e. Netherlands Nutrition Centre, National Institute for Health Promotion (NIGZ) and Netherlands Institute for Sport and Physical Activity (NISB). Several teachers pre-tested one or more draft versions of the lessons in the school class.

Nutrients 2016, 8, 12

3 of 17

The intervention EF! comprised a variety of theory and practical lessons on nutrition and physical activity to provide an attractive program for the children. The intervention was focused on the main behavioral changes: decreasing consumption of high-energy or high-fat foods and sugar-sweetened drinks; promoting a healthy breakfast; increasing consumption of fruits and vegetables; reducing television viewing and computer gaming/browsing; and increasing physical activities at school and outside school hours. The behavioral determinants of the TPB that were targeted were: knowledge (theory lessons and practical assignments), attitude (group discussions, food diaries), social norm (group discussions and homework assignments) and perceived behavioral control (modeling through assignments e.g., preparing a healthy meal and physical activity games). EF! was targeted at 9–11 years old children and the whole school class, no distinction was made between non-overweight, overweight or obese children. The reasons for limitation of the target group to 9–11 years olds were limited budgets and the ability of primary school children of this age category to participate in paper and pencil questionnaires, used in this research. The lessons had been implemented in the regular school program during two successive school years in grades (U.S. system) 4, 5, and 6. The program consisted of seven lessons in the first school year and nine in the second year (Table S1 in Supplementary Materials). Methods that were used included theory lessons, practical lessons, homework assignments, and involvement of parents in homework. Besides, there were two optional elements: (1) an “Extra Fit-day” with appealing activities involving parents; and (2) physical activity lessons. Examples of themes that were addressed were physical activity, computer use, nutrition, and energy balance by using experiments, assignments, videos and classroom discussions. These activities were especially designed to increase knowledge and awareness of the children, to get them involved and excited, and to involve parents and teachers in the process. 2.2. Implementation The EF! lessons were given by the school teachers. Collaborating local community health services and a sports service were trained to implement EF! and to give support to the teachers. The local services organized a meeting per school year in which the intervention materials were presented and discussed with the teachers in their region. The three national health promotion organizations supervised the implementation process by serving as a helpdesk for the local health and sports services and by monitoring the progress. Analysis of monitoring reports returned by the teachers of the intervention schools showed that the first lessons of the EF! program were delivered by most teachers, however there was a decline and only one out of four teachers delivered all lessons. The average total duration of the EF! lessons per year was 7.6 h (SD = 2.8) during 16 weeks per school in the intervention group. In the control schools, total time spent on education about healthy nutrition and physical activity per year was on average 3.3 h (SD = 3.9). When looking at the fidelity with respect to the involvement of parents in the intervention, it turned out that most children completed their homework without parents. The teachers of the intervention group were moderately positive about the EF! program (score 6.7 on a scale of 1–10). Compared to the lessons of the first school year, the second year lessons were less enjoyed by the children, 17% and 39% of the children, respectively, reported not to have enjoyed most EF! lessons. The children did not find the lessons difficult and liked the physical activity lessons and the practical lessons most. 2.3. Design A school-based, cluster randomized controlled study design was used to evaluate the effectiveness of EF!. The study was conducted from November 2009 to December 2011. The schools of the intervention group received the EF! program for two school years and the control schools followed their regular school program. As much as possible, matched pairs of schools were formed with similar socio-economic status (SES based on the national registry on neighborhood deprivation scores), educational level and urbanization of the region and randomized. If no similar pairs could be formed,

Nutrients 2016, 8, 12 Nutrients 2016, 8, 0000 

4 of 17

children. The study was approved by the Medical Ethics Committee of Leiden University Medical  matching at group level was sought. Informed consent procedures were followed for all children. The Center (LUMC).  study was approved by the Medical Ethics Committee of Leiden University Medical Center (LUMC). 2.4. Participants 2.4. Participants  A total of about 500 schools were approached for participation in the study, of which 76 agreed A total of about 500 schools were approached for participation in the study, of which 76 agreed  to participate (see Figure 1). Eleven schools dropped out before the randomization procedure. to participate (see Figure 1). Eleven schools dropped out before the randomization procedure. The  The remaining schools were assigned randomly to the intervention or control condition. Before remaining  schools  were  assigned  randomly  to  the  intervention  or  control  condition.  Before  the  the research started, 20 schools dropped out, resulting in 23 schools in the intervention group and 22 research started, 20 schools dropped out, resulting in 23 schools in the intervention group and 22 in  in the control group at baseline. Reasons for schools declining were changes in personnel, the intensity the control group at baseline. Reasons for schools declining were changes in personnel, the intensity  of the project, or unwilling to sign a written agreement stating that the school would adhere to the of the project, or unwilling to sign a written agreement stating that the school would adhere to the  research At the  the final  final measurements,  measurements, there  there were  were 17  17 and  and 21  21 schools  schools left,  left, research  and and  intervention intervention  protocol. protocol.  At  respectively. The reasons for school dropout after the study had started were change of teacher from respectively. The reasons for school dropout after the study had started were change of teacher from  grade 4 to 5 and lack of time. grade 4 to 5 and lack of time. 

  Figure 1. Flow diagram of schools and participants.  Figure 1. Flow diagram of schools and participants.

 

4 of 17

Nutrients 2016, 8, 12

5 of 17

2.5. Assessments The primary outcome measures were nutrition, physical activity, sedentary behavior (inactivity and screen time) and behavioral determinants. Behavior was chosen as a primary outcome measure because the intervention was primarily aimed at behavioral change in a population with a majority of non-overweight children. BMI (prevalence of overweightness/obesity) and waist and hip circumference were secondary outcome measures. The children were assessed on four occasions during the study. The baseline measurement took place from November 2009 to December 2009 (T0). A school could start the intervention only after the baseline measurement had taken place. An intermediate follow-up took place twice, at the end of the first school year in which the children received EF! (T1a; May–July 2010) and at the end of the second school year, when the intervention schools finished the EF! program (T1b; May–July 2011). The measurement at T1b was limited and included only self-report measurement of behaviors and their determinants. The last follow-up measurement took place six months later in November–December 2011 (T2). The questionnaire was administered on all four occasions in the total study population. The anthropometric measurements were conducted three times, at T0, T1a and T2. Dietary intake and physical activity measurements using one-day records and accelerometers took place at T0 and T2, in random subsamples of the total study population. Since complete measurements would be too expensive, subgroups of approximately five to six children per school class participated in detailed measurements of dietary intake and physical activity each time. The selection procedure of the subsamples was performed in a structured manner. Parents of 10 randomly selected children per school class received a letter to gain informed consent to participate in additional measurements to get more information about the children’s dietary intake and physical activity. If parents did not respond within two weeks, they received a reminder. The selection procedure stopped when there were five to six participants per school class. This procedure was repeated at T2 and again a random sample was recruited. This resulted in cross-sectional measurements in two independent subsamples at T0 and T2. The required number of five to six children per class each time was based on sample size calculations for multilevel analysis using online (RIVM) dietary data from the Dutch National Food Consumption Survey. An overview is provided in Table 1. Table 1. Overview of assessments and time points of the intervention. T0

T1a

T1b

T2

Assessment

Whom

0 Month

6 Months

18 Months

24 Months

Questionnaire Anthropometry Dietary record Accelerometer Intervention

All children from each class All children from each class Random sample from each class Random sample from each class

x x x x Start after T0

x x

x

x x x x

2.5.1. Dietary Intake Dietary intake was assessed twice in random subsamples consisting of 248 children with a one-day food diary at T0 and 224 children at T2. The children and parents received a food diary at home with instructions and an example food diary. Parents were instructed to help the child fill out the food diary when this was needed. To make the food diary as accurate and complete as possible, the day after the child filled out the food diary, an interview was conducted with the child together with a parent or caregiver by field workers during a home visit. The field workers checked the diary, probed for possibly forgotten items and, if the diary was very incomplete, they conducted a 24-h recall. Field workers were student dieticians, specifically trained for this study. The data of the food diaries were systematically structured according to the Dutch food-based dietary guidelines [23] and all food items were coded based on the food items of the Dutch Food Composition Database [24]. The amount consumed per food was recorded in household measures or standard or natural units and converted into grams using a Dutch manual [25]. Furthermore, time and

Nutrients 2016, 8, 12

6 of 17

place of each food consumption were registered. The interviewers were blinded with respect to group status of the child’s school (intervention or control) and were equally divided between the control and intervention schools. Training and supervision of the interviewers and plausibility checks of the food diaries were conducted by an experienced dietician. 2.5.2. Physical Activity Measurement of physical activity succeeded in 122 children at T0 and 140 at T2 using a one-dimensional accelerometer; the ActiGraph. The ActiGraph measures frequency, duration and intensity of physical activity based on counts per minute, i.e. number of conversions of movements into electrical signals. In this study, counts per minute were collected every 15 s. In this way, also short durations of high activity were registered, which are very common in children. Parents were instructed to attach the ActiGraph to their child’s right hip by an elastic waist belt. Children should wear the ActiGraph during at least three days and remove the ActiGraph when water was involved and during sleeping time. The ActiGraph measurements were not always successful due to improper use by the child and technical problems. 2.5.3. Anthropometric Measurements Weight, height, and waist circumference measurements were completed with children in a private room at school by two trained fieldworkers. Weight was measured without shoes in clothing to the nearest 0.1 kg using a portable digital scale (SECA). Height was measured without shoes, to the nearest 0.1 cm using a portable stadiometer (SECA). Waist and hip circumference were measured to the nearest 1 mm with a flexible tape. The waist circumference was measured midway between the lower rib and the top of the iliac crest. The hip circumference was measured at the maximal circumference over the buttocks. BMI SD scores were used to categorize children as underweight, normal weight, overweight, or obese using international gender and age specific thresholds [26]. 2.5.4. Questionnaire All children of each participating school class were invited to fill out questionnaires in the classroom during school-time under guidance of the teachers comparable to a normal school test. The questionnaires assessed their general characteristics (gender, age, country of birth of the child and parents), three categories of behavior (physical activity, inactivity, and dietary behavior) and six behavioral determinants derived from the TPB (knowledge, affective and cognitive attitudes, perceived social norm, perceived behavioral control and intention). Health behavior was measured using standardized questionnaires developed by the Dutch local and national health monitor [27]. Children were asked how many days per week they were having breakfast, fruit, vegetables, sweet drinks, savory and sweet snacks and how many portions they consumed on average in a day. We studied the effect on daily breakfast or daily consumption per food item. For analysis, only the “How many days a week do you eat. . . ?” question was taken into account due to skewness of the variables. Physical activity included questions on days per week and time per day spent on sports, outdoor play and walking or cycling to and from school. These were combined into a dichotomous outcome measure representing the proportion of children that were physically active at least 60 min each day of the week. This cut-off corresponds to the Dutch Healthy Exercise Norm (840 min/week). The Dutch recommendation for screen time for children is maximum 2 h a day, corresponding to 840 min per week.

Nutrients 2016, 8, 12

7 of 17

The questions on behavioral determinants of lifestyle behaviors were adopted from other questionnaires developed in the context of overweightness and obesity prevention in the Netherlands, such as scales based on determinants of behavior change taken from the Theory of Planned Behavior (Table S2 in Supplementary Materials) [28]. An example of an item on affective attitude toward behavior is “I find a breakfast tasteful”. We also asked the children their cognitive attitude toward the frequency of behavior such as: “Do you think that you have breakfast often enough?” Knowledge of the children was measured by multiple-choice questions about the Dutch Food Pyramid (Dutch: Schijf van Vijf ), breakfast, healthy snacks, fruit and vegetables norm, physical activity norm, types of physical activity and maximum screen time. These questions correspond to the topics that were discussed during the lessons. 2.6. Statistical Analysis Energy intake, macronutrients and contribution of the food groups were calculated with the Dutch Food Composition Database [24] using the SAS application VEVES (Voeding Enquêtes Verwerkings Systeem). Food diaries that were classified as unreliable by the interviewer were excluded from the analyses. All accelerometer data were processed using the Mahuffe 1.9.0.3 software program. The data were included in the analyses if the accelerometer was worn for at least 500 min per day. Periods of zero activity counts (ě10 min) and sleeping periods were excluded. Data were expressed as mean counts per minute and as mean time spent on different intensity activities using age-specific cut off points [29,30]. Factor analysis was performed and Cronbach’s alphas were calculated to determine the behavioral determinants scales. Factor analysis showed that on the whole the behavioral determinants of specific behaviors loaded on separate factors. Therefore for each behavior a composite behavioral scale was constructed by summing up the scores of all determinant scales except knowledge into an overall score. This was done to limit multiple testing, given the many behavioral determinant variables. The Cronbach’s alphas of the composite scales varied from 0.72 to 0.77 except for sedentary behavior (screen time) that had a relatively low Cronbach’s alpha of 0.41. For dietary behavior and physical activity a score above the fiftieth percentile was considered a positive score on the composite scale. The sum score of the determinants of sedentary behavior was the only variable with a normal distribution. For this variable we used a continuous composite score. Because schools were the sampling unit, outcome analyses were conducted using multilevel regression models, with schools included as a random effect. The model used all of the available information (i.e., information from participants with both complete and incomplete data) to simultaneously estimate both the missing data model and the data analysis model. In the regression models, the dependent variables were dietary intake (nutrients and food groups), physical activity, sedentary behavior (inactivity and screen time), anthropometric measures and behavioral determinants at follow-up, with group (intervention or control group) as independent variable. Linear mixed effects models were used where anthropometric and behavioral (determinants) outcomes at T1 or T2 were predicted by fixed effects for group (control vs. intervention), baseline measurements at T0, sex and age as well as the random (nested) effect of school. Other covariates included in the model for the behavioral outcomes were ethnicity and (school) socio-economic status. Linear mixed effects models were also used where dietary intake (food diary) and physical activity (ActiGraph) were predicted by fixed effects for group (control vs. intervention), time (T0, T2: cross-sectional time points), the interaction between group and time, sex and age, as well as the random (nested) effect of school. An additional covariate included in the model for the dietary outcomes was total energy intake. For the physical activity outcomes other covariates that were included in the model were, BMI SD score, and percentage of weekdays the child had worn the ActiGraph. A two-sided p value of